Sheet feeding mechanism



April 1970 NOBUYUKI YANAGAWA 3,507,488

SHEET FEEDING MECHANISM 2 Sheets-Sheet 1 Filed Feb. 12, 1968 FIG. I

W' 1? BY g4 ATTORNEYS April 1970 NOBUYUKI YANAGAWA 3,507,488

SHEET FEEDING MECHANISM 2 Sheets-Sheet 3 Filed Feb. 12, 1968 FIG. 3

FIG. 4

INVENTOR BY g y ATTORNEYS United States Patent 3,507,488 SHEET FEEDINGMECHANISM Nobuyuki Yanagawa, Tokyo, Japan, assignor to Kabushiki KaishaRicoh, Tokyo, Japan Filed Feb. 12, 1968, Ser. No. 704,769 Claimspriority, application Japan, Feb. 16, 1967, 42/ 12,890 Int. Cl. B65h3/06 U.S. Cl. 271-36 1 Claim ABSTRACT OF THE DISCLOSURE A sheetfeedingmechanism for a copying machine or the like. The feeder is of the typewhich consists of rotatable rollers which rest upon the top sheet of astack of sheets and upon rotation of the rollers which frictionallyengage the top sheet, the top sheet is moved off the stack of sheets andinto the copying machine or printing machine. The rollers are mounted ona rotatable shaft which is transverse to the path of movement of the topsheet of the stack which shaft is supported on pivoted arms. At leastone of these arms has an arm projecting from it adjacent to the pivotpoint of the supporting arm, and the short arm is adapted to becontacted by a spring biased L-shaped sliding member which serves tobias the transverse shaft with its rollers in a direction to relieve thestack of sheets of some of the weight of rollers and supporting members.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a sheet feedingmechanism illustrating one embodiment of the invention;

FIG. 2 is a cross sectional view taken along the dotdash line 22 of FIG.1;

FIG. 3 is an end view looking from the plane marked 33 of FIG. 1; and

FIG. 4 is a cross sectional view along dot-dash line 4-4 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION This invention relates to animprovement of a sheet feeding mechanism, particularly of a type inwhich r0- tatable rollers activated by suitably transmitted power areadapted to be pressed on the top of a pack of sheets mounted on a feedtable so as to feed the topmost sheet in the pack forward in timedrelation with the rotation of said rollers.

The present invention will now be described in further detailshereinbelow in reference to an example embodiment shown in theaccompanying drawings.

Referring now to FIG. 1, a planetary feed table 1 has upstanding sideends or walls 1a and 1b, one of which is pierced through by atransmission shaft 2. The shaft 2 is horizontally supported by a pair ofside plates 3 for a U-shaped bearing fixed on a suitable position on thefeed table. On the other side wall 1b across the feed table from shaft 2is fixedly mounted an axil 2a which serves as a pivot for one end of oneof the pair of oscillating arms 4, the remaining oscillating arm beingpivoted likewise on the aforesaid shaft 2. Said oscillating arms arerespectively connected integrally with a rod 4a and are furtherprovided, at their free ends, with a shaft 6 carrying coaxially aplurality of freely rotatable rollers 5. The circumference of therollers 5 are adapted to be pressed on the top surface of the topmostsheet in the stack of sheets loaded on the feed table with their forwardends aligned.

On one end of the roller shaft 6 is provided a chain carrying gear 9a(refer FIG. 1) which is equipped, in the 3,507,488 Patented Apr. 21,1970 interior thereof, coaxially with an irreversible rotary mechanism 8such as illustrated in FIG. 4. The gear 911 is coupled, through atransmission chain 11, with the motion of the like gear 16 mounted onthe shaft 2.

It follows that the rotation of the shaft 6 in a suitable directionactivates the like motion of the rollers 5, causing the topmost sheet inthe stack 7 pressed by the latter to be moved in the direction of anarrow shown in FIG. 1. The rollers take a position shown in dot and dashlines in FIG. 4 when the stack is high and another position shown inactual lines when the roller supporting arm 4 takes a horizontalposition as the stack is depleted.

Supposing now that the rollers 5 are pressed on the top of the stackunder their own weight and the weight of their supporting arms 4, andthat the height of the stack is diminished, then the roller supportingarms are near a horizontal position from their original slantingposition, the rotary coefiicient of the roller supporting arm around theshaft 2 will increase, causing the pressure of the rollers against thestack to increase correspondingly. Let the rotary force and amount forrollers around their axis be same, changes in the pressure of therollers against the stack cause variations in the distance moved by thesheets in a forward direction by virtue of their frictional engagementwith the rotating rollers. Needless to mention, it is desirable to keepsuch distance invariable from the topmost sheet to the last sheet in thestack.

In a preferred embodiment of a copying machine employing a sheet feedingmechanism such as contemplated herein, the machine will be designed suchthat an original form fed thereinto will be adapted to activate amicroswitch provided in a passage channel of the original form forrotating a transmission which will cause the feed rollers to rotate forfeeding a copy sheet forwardly, whereupon the copy sheet will be adaptedto be overlaid with the aforesaid original form with their respectiveleading edges aligned to each other and then fed to a rotating printingcylinder for revolving around thereof to complete a printing cycleautomatically.

With a copying machine such as described above, variations in thefeeding distance of each copy sheet delivered by aforesaid frictionalfeed rollers may cause misalignment of the copy sheet from the overlaidoriginal form, resulting in considerable difficulty. In a duplicatorsimilarly having an automatic sheet feeding mechanism of the typedescribed heretofore, it may be readily understood that the samevariations will cause various inconveniences and disadvantages.

In an example embodiment of this invention illustrated in theaccompanying drawings, the roller supporting arm 4 is provided, at oneside edge proximate to its base portion, with an extension 12 formedintegral therewith.

The extension 12 is engaged with an abutment of a metal mounting 13mounted freely slidable on the feed table. Provided between said metalmounting and a suitable stationary member such as a stud 14 on the feedtable is a contractable spring 15 which tends to keep the rotarycoefficient of the roller supporting arm 4 around shaft 2 uniform. Inother words, the contracting force of the spring 15 tends not only toabate the dead load of the roller supporting arm 4 but also to balance,under increasing contracting force as the roller supporting armapproaches its horizontal position, with an increasing rotarycoefiicient of said roller supporting arm, with a result that thepressure exerted by the rollers on the stack will always be madeuniform.

The contracting force of the spring 15 may be variable by permitting, asshown in FIG. 4, the stud 14 which holds one end of the spring onto thefeed table 1, to be adjustably mounted on the feed table for freesliding movement.

The manner in which the spring is extended is, of course, not limited tothe illustrated example, but other mode of effecting the same resultwill be readily conjecturable for those skilled in the art withoutdeparting from the true spirit and the scope of the utility model. Forexample, a spring can be wound around a rotary axis 211 for the rollersupporting arm 4 with one end attached to said axis, the other endleaned pressingly against a pin planted approximate to the base portionof said roller supporting arm 4.

What is claimed is:

1. In a sheet feeding mechanism for a stack of sheets, comprisingpivoted mounted arms a transverse rotatable shaft mounted on pivotedarms, rollers on said shaft adapted to rotate with said shaft and tocontact the top surface of the top sheet on a stack of sheets to be fedinto a copying machine, an arm projecting from at least one of thepivoted arms near its pivot point, a sliding, spring actuated, L-shapedmember positioned to contact said point upon movement of the said memberby said spring and to bias said pivoted arm in a direction to raise saidrollers from the stack of sheets and thus relieve said sheets of some ofthe weight of said rollers and their supporting means.

References Cited UNITED STATES PATENTS 2,808,260 10/1957 Runzi 271-363,062,534 11/1962 Benson 27136 3,269,591 8/1966 Harter 27136 RICHARDAEGERTER, Primary Examiner

